This units says that it adds 1.3 dB of gain. Honestly, I hate to say it is a lie, but it actually cut my gain by what seemed to be half. My sub went from "awesome thumping" to " gentle bass" as soon as I installed it. As a sanity check, I un-installed and reinstalled it 4 times and compared the sound output each time, same song, same settings. Yup, definitely a decrease in the sound. Needless to say, I will not be installing it. My sub came with a remote gain control and I found out that you can just turn it all the way down before each circumstance above, to avoid the popping. I might even send in my sub to the MFG to have them adjust it for FREE.
Pros: I had an annoying pop from my powered sub every time that I would turn off my stereo, turn on my stereo, switch input sources (CD, USB, Radio, etc.), volume from 1 to 0, and volume from 0 to 1. It was pretty disturbing. I installed this unit and BAM the popping was never heard of again.
Cons: It cut my signal gain, regardless of what it says (adds 1.3dB).